{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T06:01:52Z","timestamp":1785132112314,"version":"3.55.0"},"reference-count":28,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T00:00:00Z","timestamp":1785110400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Bioeng. Biotechnol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Markerless motion capture systems offer a promising alternative to traditional marker-based gait analysis by reducing technical burden and improving clinical applicability. Monocular two-dimensional pose estimation (2D-PE) apps represent an emerging low-threshold solution; however, their accuracy against established reference systems remains insufficiently validated.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>This study evaluated the concurrent validity of a CE-registered monocular 2D-PE system (Orthelligent\u00ae VISION, OPED GmbH) relative to a multi-camera markerless 3D motion capture system (3D-MoCap; Qualisys\/Theia3D) regarding spatiotemporal and sagittal kinematic gait parameters in patients with knee osteoarthritis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Thirty patients (13 men, 17 women; 64.5 \u00b1 7.1 years) with radiologically confirmed anteromedial knee osteoarthritis (Kellgren\u2013Lawrence grade \u22652) underwent simultaneous treadmill gait assessment using both systems. Agreement was quantified using intraclass correlation coefficients (ICC), Bland\u2013Altman analysis, and one-dimensional statistical parametric mapping (SPM1D) of time-normalized joint-angle trajectories, with additional 0\u00b0 normalization at initial contact for waveform-shape comparison.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Cadence, walking speed, and step length demonstrated moderate-to-excellent ICC values (0.74\u20130.95) with small mean biases. Temporal parameters (stance time, step time) yielded ICC values close to 0 with wide confidence intervals. Following 0\u00b0 normalization at initial contact, knee kinematics showed moderate-to-good reliability (ICC \u2248 0.67\u20130.74), while hip and ankle ICCs were generally low. SPM1D analyses revealed only brief, phase-specific differences between systems, predominantly during loading response and terminal swing.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>The 2D-PE system provides sufficient concurrent validity for selected spatiotemporal parameters and sagittal knee waveform shape, supporting its use as a clinical screening and monitoring tool for relative changes in joint motion rather than for precise absolute angle quantification.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fbioe.2026.1869878","type":"journal-article","created":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T05:41:13Z","timestamp":1785130873000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Gait assessment using a 2D video-based pose estimation app in comparison to a markerless motion capture system in subjects with osteoarthritis of the knee \u2013 a pilot study"],"prefix":"10.3389","volume":"14","author":[{"given":"Mathis","family":"Wegner","sequence":"first","affiliation":[{"name":"Department of Orthopaedics and Traumatology, University Medical Centre Schleswig-Holstein, Campus Kiel","place":["Kiel, Germany"]},{"name":"Orthopedic Research Center, Kiel University","place":["Kiel, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Madita","family":"Molt","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics and Traumatology, University Medical Centre Schleswig-Holstein, Campus Kiel","place":["Kiel, Germany"]},{"name":"Orthopedic Research Center, Kiel University","place":["Kiel, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Clint","family":"Hansen","sequence":"additional","affiliation":[{"name":"Department of Neurology, UKSH Campus Kiel, Kiel University","place":["Kiel, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Florian","family":"Gellhaus","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics and Traumatology, University Medical Centre Schleswig-Holstein, Campus Kiel","place":["Kiel, Germany"]},{"name":"Orthopedic Research Center, Kiel University","place":["Kiel, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maciej J. 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